Radiant gas burner with internal mixture distributing means



Jam. 26, 1965 c. sz LL 3,167,110

RADIANT GAS BURNER WITH INTERNAL MIXTURE DISTRIBUTING MEANS Original Filed Fuly 11, 1956 2,0 37 INVENTOR 5' (214mm 5251.

BY 7%fiw ATTORNEYS 3,167 110 RADIANT GAS BURNlER WITH INTERNAL MIXTURE DISTRIBUTING MEANS Charles Snell, Bedford Heights, Ohio, assignor to Ilupp Corporation, Cleveland, Ohio, a corporation of Virginia This invention relates to gas burners and more particularly to gas burners which have a radiation surface rendered incandescent by the combustion of fuel on or adjacent to the radiation surface.

In one form of burner of this type with which the invention is particularly concerned, a gas-air mixture is fed to a mixing and distributing chamber, one wall of which is formed by a plurality of perforated ceramic blocks through which the fuel and air mixture passes. Combustion occurs on or adjacent the outer surface of the block or blocks and raises the temperature of the outer block surface to a level at which heat energy in the infra-red spectrum is emitted.

Combustion in such burners is effected with 100% primary air supplied from the mixing chamber. Accordingly, it is of critical importance for optimum efficiency that the fuel-air mixture be substantially homogeneous as it is supplied to the burner blocks and that the mixture be supplied at uniform pressures and quantities to all parts of the burner surface.

It is a principal purpose and object of the present invention to provide improved burners including novel means for directing the fuel-air mixture uniformly to all areas of the burner surface.

The improved fuel-air mixture distributing apparatus of the present invention has particular application to one form of burner now in use which includes a mixing cham ber of elongated rectangular form, the fuel air mixture being introduced into the mixing chamber through a mixing tube which extends along a substantial portion of the longitudinal axis of the mixing chamber and opens into the chamber adjacent one end thereof. This prior burner includes arcuate battles which intercept the fuel-air mixture issuing from the outlet end of the mixing tube and directs it back toward the opposite end of the chamber. While these prior burners, which are the most efficient burners of this type known prior to the present invention, operate successfully and are in widespread use nevertheless actual observation has shown that dark areas often appear in the face of the otherwise bright incandescent burner surface. Such areas indicate an insufficient fuel supply.

It is a more specific object of the present invention to provide improved fuel distributing means for burners of the type mentioned above which correct the above stated conditions and distribute the fuel-air mixture to the burner surfaces in a manner to produce a pattern of uniform brightness over the entire surface area of the burner elements.

It is also an object of the present invention to provide improved fuel-air mixture distributing means which may be incorporated in existing burners without substantial modification.

It is a further object of the present invention to provide improved fuel-air distributing means which are simple in construction and which may be manufactured and installed at low cost.

Additional objects and advantages will become apparent as the description proceeds in connection with the accompanying drawings in which:

FIGURE 1 is a plan view of the burner of the present atcnt G tion. The bottom, side and end walls 22, 24, 26 and 28 respectively of the housing form a chamber 30 of generally rectangular form. Formed integrally with the housing 20 and extending along the longitudinal axis thereof is a venturi tube 32. At its outer end the venturi tube 32 opens through the end wall 28 of the housing 20 in coaxial alignment with a fuel nozzle assembly 34 suitably secured to a boss 36 formed integrally with the adjacent end of the housing 20. Flow of gaseous fuel from the nozzle 34 entrains air entering "through an open ing 37 formed in the lower side of the outer end of the venturi tube 32. r

The inner end of the venturi tube 32 opens into the chamber 30 opposite a central projection 38 formed between two arcuate flow directing surfaces 40 which divide the mixture flowing out of the inner end of the venturi tube and directs it rearwardly toward the opposite end of the chamber 30. The fuel-air mixture is intercepted and directed upwardly, by a pair of transverse integral baflles 41 extending from the housing side walls to the venturi tube.

A flat plate 42 is secured by a screw 46 to the burner housing 20 and projects over the flow directing walls 40 to further guide and facilitate the distribution of the fluid issuing from the outlet end of the venturi tube 32.

The open wall of the mixing chamber 30 is closed by a plurality of burner blocks or radiants 48, the outer edges of the blocks being supported on a ledge 50 extending around the housing and the inner corners of the blocks being secured by screws 52,to bosses formed in the upper surface of the venturi tube 32.

The blocks 48 which are preferably ceramic tile are provided with a plurality of through passages 54 through which the gaseous fuel-air mixture supplied by the venturi tube 32 issues from the chamber 30. Combustion of the mixture occurs on or adjacent the outer surface of the radiants 48 heating the surfaces to a temperature in the neighborhood of 1600" F. to 1800" F. at which temperature they emit heat energy in the infra-red spectrum.

Actual tests have shown that while the fuel distribution system thus far described is adequate for many purposes nevertheless it is not uniform as indicated by dark areas on certain of the radiants.

In accordance with the present invention these deficiencies of the prior distribution apparatus are corrected by the provision, in combination with the venturi tube 32, the flow directing surfaces 40 and the plate 42, of battle members 56. The baffles 56 are preferably spot welded to the under surface of the plate 42 and extend downwardly and outwardly therefrom at an angle of approximately 60 from the plane of the plate 42. The side edges of the baffles 56 are spaced substantially equally from the side walls of the housing and from the adjacent surfaces of the venturi tube 32 so as to dispose the bafiies substantially centrally of the duct formed in the housing 30 at each side of the venturi tube 32. The baffles 56 may conveniently be made of material known in the trade as expanded metal which, as is well known in the art, is formed by cutting a metal sheet at spaced points and stretching the metal so as to form a plurality of openings 58 between adjacent strips 60 of the parent metal. In the formation of the expanded metal the longitudinal stretching of the metal twists the strips 60 so as to dispose them at an angle of approximately 30 with the plane of the parent metal. Accordingly when the metal is installed as shown in the drawings the individual strips 60 are substantially vertical thus effectively deflecting the fuel-air mixture directly upwardly toward the adjacent radiants. While the expanded metal has proved to be satisfactory and inexpensive nevertheless its essential function of intercepting portions of the fuel-air mixture and directing them upwardly toward the radiants may be accomplished by other equivalent perforated baffle arrangements which are within the scope of the present invention.

Tests have shown that baffles 56 deflect a portion of the fuel-air mixture to the region previously insufficiently supplied to effect a substantially completely uniform distribution of the fuel-air mixture as evidenced by the fact that the entire outer surface of the radiants 48 is of uniform brightness.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

This application is a continuation of co-pending application Serial No. 597,185 filed July 11, 1956 for Burners and now abandoned.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a gas burner, a dish-shaped main body member of generally rectangular form having a bottom wall, side walls and end walls, one of said end walls being imperforate, the other of said end walls having an opening formed therein, a mixing tube extending from said opening toward said impcrforate end wall, one end of said tube being disposed adjacent said imperforate end wall, flat burner means forming the top wall of said burner, means for introducing fuel and air into said mixing tube, said imperforate end wall having concavely curved parts positioned opposite a portion of said burner means and extending in opposite directions toward the opposite side walls of said body member operable to intercept the fuelair mixture issuing from said one end of said tube and for dividing said mixture into separate streams and directing said streams toward said other of said end walls, imperforate bafiles extending over said concave parts substantially parallel with the inner surface of said burner means and perforate baffles forming an extension of said imperforate baflles and extending downwardly toward said bottom wall of said body member and away from said burner means, said perforate baffles having surfaces for directing portions of said streams away from said bottom wall and toward the adjacent portions of said burner means.

2. The combination according to claim 1 wherein said perforate bafiles comprise sheets of expanded metal.

3. In a gaseous fuel burner, a generally rectangular mixing chamber for gaseous fuel and air having bottom, side and end wall portions, substantially flat perforated burner means forming a substantially fiat top wall portion of said mixing chamber, a mixing tube adapted to convey a mixture of fuel and air and having an outlet end adjacent one end wall portion of said chamber, said mixing tube extending through said chamber substantially centrally thereof, means formed integrally with said one end wall portion of said chamber opposite a portion of said perforated burner means forming flow directing surfaces for dividing the fuel-air mixture issuing from said tube into two primary streams, means forming imperforate distributing surfaces spaced a substantial distance from the inner surface of said burner means and extending over a portion of each of said streams adjacent said fiow directing surfaces in a direction generally parallel with said burner means to prevent the direct impingement of said streams on said portion of said burner means, and a pair of substantially planar perforated baffles, said baffles being mounted within said chamber at opposite sides of the outlet end of said mixing tube, one of said baffles beinmounted to extend into one of said primary streams and the other of said baffles being mounted to extend into the other of said primary streams, each of said bafiies having deflector surfaces for intercepting at least a portion of the respective streams into which they extend downstream of said distributing surfaces and for directing the intercepted portion of said stream toward said portion of said burner means.

4. In a gas burner a dish-shaped body member forming a mixing chamber of generally rectangular form having a bottom wall portion and side wall portions projecting upwardly from said bottom wall portion and terminating in a flat rim, a mixing tube having one end in communication with an opening in said body member and extending centrally of said mixing chamber along said bottom wall portion, substantially flat perforated burner means mounted on said rim and forming a substantially flat top wall of said burner, means for introducing fuel and air into said one end of said mixing tube, a projection extending upwardly from said bottom wall portion toward a portion of said burner means and positioned opposite the outlet end of said mixing tube, the top of said projection forming a shelf spaced from and substantially parallel to said fiat burner means, smoothly curved wall portions connecting said projection to the opposite side wall portions of said mixing chamber operable to intercept a substantial portion of the fuel-air mixture issuing from the adjacent end of said mixing tube and to divide said mixture into separate streams which flow along the body member side wall portions and along the sides of said mixing tube, and flow directing means secured to said shelf, a portion of said flow directing means being substantially parallel with the inner surface of said burner means and extending over said shelf and said curved surfaces and a second portion of said flow directing means being positioned out of the path of said mixture as it flows from said mixing tube to said curved surfaces and in the path of portions of said mixture after they have left the region of said curved surfaces and being inclined to extend away from said burner means and said latter portion of said flow dividing means being perforated to provide a series of openings through which portions of said mixture flow and to provide a series of deflector surfaces for directing portions of said mixture toward the adjacent portions of said burner means, said flow directing means terminating at one edge in the region of the outlet end of said mixing tube, and spaces being provided between said flow directing means and the adjacent portions of said body member whereby other portions of said fuel-air mixture flow past said flow directing means and pass freely to the inner surface of said fiat burner means, and said fuel-air mixture is distributed substantially uniformly to all portions of said flat burner means.

References Cited in the file of this patent UNITED STATES PATENTS 1,077,073 Hook Oct. 28, 1913 1,677,156 Vaughn July 17, 1928 1,977,947 Lutenbacher Oct. 23, 1934 2,533,104 Golden et al Dec. 5, 1950' 2,621,722 Abrams Dec. 16, 1952 2,870,830 Schwank Jan. 27, 1959 

4. IN A GAS BURNER A DISH-SHAPED BODY MEMBER FORMING A MIXING CHAMBER OF GENERALLY RECTANGUALR FORM HAVING A BOTTOM WALL PORTION AND SIDE WALL PORTIONS PROJECTING UPWARDLY FROM SAID BOTTOM WALL PORTION AND TERMINATING IN A FLAT RIM, A MIXING TUBE HAVING ONE END IN COMMUNICATION WITH AN OPENING IN SAID BODY MEMBER AND EXTENDING CENTRALLY OF SAID MIXING CHAMBER ALONG SAID BOTTOM WALL PORTION, SUBSTANTIALLY FLAT PERFORATED BURNER MEANS MOUNTED ON SAID RIM AND FORMING A SUBSTANTIALLY FLAT TOP WALL OF SAID BURNER, MEANS FOR INTRODUCING FUEL AND AIR INTO SAID ONE END OF SAID MIXING TUBE, A PROJECTION EXTENDING UPWARDLY FROM SAID BOTTOM WALL PORTION TOWARD A PORTION OF SAID BURNER MEANS AND POSITIONED OPPOSITE THE OUTLET END OF SAID MIXING TUBE, THE TOP OF SAID PROJECTION FORMING A SHELF SPACED FROM AND SUBSTANTIALLY PARALLEL TO SAID FLAT BURNER MEANS, SMOOTHLY CURVED WALL PORTIONS CONNECTING SAID PROJECTION TO THE OPPOSITE SIDE WALL PORTIONS OF SAID MIXING CHAMBER OPERABLE TO INTERCEPT A SUBSTANTIAL PORTION OF THE FUEL-AIR MIXTURE ISSUING FROM THE ADJACENT END OF SAID MIXING TUBE AND TO DIVIDE SAID MIXTURE INTO SEPARATE STREAMS WHICH FLOW ALONG THE BODY MEMBER SIDE WALL PORTIONS AND ALONG THE SIDES OF SAID MIXING TUBE AND FLOW DIRECTING MEANS SECURED TO SAID SHELF, A PORTION OF SAID FLOW DIRECTING MEANS BEING SUBSTANTIALLY PARALLEL WITH THE INNER SURFACE OF SAID BURNER MEANS AND EXTENDING OVER SAID SHELF AND SAID CURVED SURFACES AND A SECOND PORTION OF SAID FLOW DIRECTING MEANS BEING POSITIONED OUT OF THE PATH OF SAID MIXTURE AS IT FLOWS FROM SAID MIXING TUBE TO SAID CURVED SURFACES AND IN THE PATH OF PORTIONS OF SAID MIXTURE AFTER THEY HAVE LEFT THE REGION OF SAID CURVED SURFACES AND BEING INCLINED TO EXTEND AWAY FROM SAID BURNER MEANS AND SAID LATTER PORTION OF SAID FLOW DIVIDING MEANS BEING PERFORATED TO PROVIDE A SERIES OF OPENING THROUGH WHICH PORTIONS OF SAID MIXTURE FLOW TO PROVIDE A SERIES OF DEFLECTOR SURFACES FOR DIRECTING PORTIONS OF SAID MIXTURE TOWARD THE ADJACENT PORTIONS OF SAID BURNER MEANS, SAID FLOW DIRECTING MEANS TERMINATING AT ONE EDGE IN THE REGION OF THE OUTLET END OF SAID MIXING TUBE, AND SPACES BEING PROVIDED BETWEEN SAID FLOW DIRECTING MEANS AND THE ADJACENT PORTIONS OF SAID BODY MEMBER WHEREBY OTHER PORTIONS OF SAID FUEL-AIR MIXTURE FLOW PAST SAID FLOW DIRECTING MEANS AND PASS FREELY TO THE INNER SURFACE OF SAID FLAT BURNER MEANS, AND SAID FUEL-AIR MIXTURE IS DISTRIBUTED SUBSTANTIALLY UNIFORMLY TO ALL PORTIONS OF SAID FLAT BURNER MEANS. 